The engine immobiliser system is designed to prevent the vehicle from being stolen. This system uses a transponder key ecu that stores the key codes of authorized ignition keys. If an attempt is made to start the engine using an unauthorized key, the ecu sends a signal to the ecm to prohibit fuel delivery and ignition, effectively disabling the engine.

The transponder key coil receives this signal, the transponder key amplifier amplifies it, and then the signal is transmitted to the ecu. The ecu matches the key's id code with the vehicle's id code, which was previously registered in the ecu and then communicates the results to the ecm using sfi communication.
Engine immobiliser system
How to proceed with troubleshootingAuto lsd indicator light does not come on
Description
Refer to the description of "auto lsd indicator light remains on" (see page
bc-164).
Wiring diagram
Refer to the auto lsd indicator light circuit (see page bc-165).
Inspection procedure
Check can communication system
Check if the can communication system dtc is ...
Dtc check / clear
Notice:
When the diagnosis system is changed from normal
mode to check mode or vice versa, all dtcs and freeze
frame data recorded in normal mode are erased. Before
changing modes, always check and make a note of any
dtcs and freeze frame data.
Hint:
Dtcs which are stored in the ecm can be ...
Removal and installation of engine intake parts
If any metal particles enter inlet system parts, they
may damage the engine.
When removing and installing inlet system parts,
cover the openings of the removed parts and engine
openings. Use gummed tape or other suitable
materials.
When installing inlet system parts, check that no ...